1953278113781 has 2 divisors, whose sum is σ = 1953278113782. Its totient is φ = 1953278113780.

The previous prime is 1953278113777. The next prime is 1953278113783. The reversal of 1953278113781 is 1873118723591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1556168926225 + 397109187556 = 1247465^2 + 630166^2 .

It is a cyclic number.

It is not a de Polignac number, because 1953278113781 - 2² = 1953278113777 is a prime.

It is a super-2 number, since 2×1953278113781² (a number of 25 digits) contains 22 as substring.

Together with 1953278113783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1953278113783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 976639056890 + 976639056891.

It is an arithmetic number, because the mean of its divisors is an integer number (976639056891).

Almost surely, 2^{1953278113781} is an apocalyptic number.

It is an amenable number.

1953278113781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1953278113781 is an equidigital number, since it uses as much as digits as its factorization.

1953278113781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2540160, while the sum is 56.

The spelling of 1953278113781 in words is "one trillion, nine hundred fifty-three billion, two hundred seventy-eight million, one hundred thirteen thousand, seven hundred eighty-one".